1. Field of the Invention
The present invention relates to a vehicular seat apparatus mounted in a vehicle such as an automobile.
2. Description of the Related Art
In an automobile that is furnished with an airbag for its passenger seat, the airbag may sometimes be expected to expand if an occupant in the passenger seat is an adult. The automobile of this type must be provided with determining means that determines whether the occupant in the passenger seat is an adult or any other one (child, child seat, or other occupant). Load sensors that are formed of strain gages, for example, are used as the determining means. The load sensors are incorporated in a seat cushion of the passenger seat. Seats of this type are described in Jpn. Pat. Appln. KOKAI Publications Nos. 9-207638, 2000-280813, and 2002-337588.
The load sensors that are formed of strain gages are located between a seat slider and a seat cushion assembly, for example. The load sensors electrically detect seating loads that act on the seat cushion assembly. In some cases, however, the outputs of these sensors may be influenced by variation in the position of the seat slider or a seat mounting portion of a vehicle body, so that the accuracy of detection of occupants may be lowered.
In a seat apparatus that is provided with load sensors, the detection accuracy of the sensors is improved by performing calibration before the seat apparatus is attached to the vehicle body. Before the apparatus is attached to the vehicle body, however, the seat slider or the frame of the seat cushion may possibly be deformed under the influence of vibration that acts on the seat apparatus during transportation, for example, the dead weight of the apparatus, etc. In this case, the sensor outputs may possibly be disturbed with the seat apparatus attached to the vehicle body despite the finished calibration.
In order to deal with this problem, a proposal has been made to attach in advance the seat apparatus to a proper jig that is equivalent to the seat mounting portion of the vehicle body during the transportation or storage of the apparatus. With use of this jig, however, it entails redundant operations, such as attachment to and removal of the seat apparatus from it, as well as additional cost.
In a seat apparatus in which left- and right-hand slide rail units are provided individually with locking mechanisms, moreover, the mounting positions of the rail units may sometimes be subject to variation. This variation may possibly cause a phase difference in locking operation between the respective locking mechanisms of the two slide rail units. Thus, the locking mechanisms of the rail units cannot operate fully synchronously, so that one of the rail units may possibly fail to be fully locked (or may be half-locked, as it is called). In this case, the friction of a locking latch member of the slide rail unit causes variation in the operating force of an unlocking or release lever (operating section).